1. Field of Invention
The present invention relates to a ceramic polishing pad dresser and a method for fabricating the same, which are applied to a CMP or an abrasive polishing process, and more particularly to a ceramic diamond disk which employs ceramic as the substrate and has a plastic base.
2. Related Art
Diamonds, being one of the hardest known engineering materials, are usually used as super-abrasive for abrasive tools. For example, the polishing pad dresser used in the chemical mechanical polishing (CMP) process for fabricating semiconductor wafers or electromagnetic recording media, i.e. hard discs, is an abrasive tool with diamonds as abrasive particles. As the structure of the polishing pad dresser includes diamond particles adhered onto an abrasive particle junction surface of a disc shaped or ring-type metal substrate (or referred to as base metal), the abrasive tool for conditioning/dressing polishing pads is also called diamond disk.
For the structure of a diamond disk, conventionally, a diamond disk includes a metal substrate and diamond particles are fixed thereon by electroplating, sintering, or bonding agent layer for hard brazing. Metal material is easy to be corroded chemically, in the environment of strong-acid or strong-base slurry, the problems that the metal substrate or bonding agent layer may cause metal contamination to wafers and the diamond disk may has the risk of diamond falling due to metal corrosion are urgent to be solved. At present, researchers in the filed tend to using ceramic materials or plastic materials for the substrate of the diamond disk. For example, a sintered metal layer holding diamond particles is bonded to a substrate made of a plastic material, so as to solve the problem of chemical corrosion of the substrate. However, as the sintered metal layer exists, the high risk of contamination and diamonds falling due to chemical corrosion cannot be completely avoided. Another method of fabricating the diamond disk involves directly embedding the diamond particles into the ceramic powder of the substrate, sintering the ceramic powder by high-temperature, and finally removing the ceramic layer overlaid on the diamond particles, so as to expose the diamond particles out of the substrate and thus form a diamond abrasive layer on the ceramic substrate. Though the method can solve the aforementioned problem, the process is very complicated and the material cost is raised greatly as the overall material is ceramic. In another aspect, ceramic is quite hard, fragile, and difficult to be processed. A plurality of positioning holes or screw holes has to be formed at the back of the The diamond disk (i.e., another surface opposite to the diamond abrasive layer), so as to fit the CMP table to be mounted. However, as the ceramic material is hard and fragile, the forming the positioning holes or screw holes are difficult, and thus the manufacturing cost is increased.